As a global standard of mobile phones, 3GPP (3rd Generation Partnership Project) defines the standards of the WCDMA communication system. The architecture and functionality of the WCDMA communication system have been variously stipulated (for example, cf. Mobile Wireless Internet Forum, Open RAN Architecture in 3rd Generation Mobile Systems Technical Report MTR-007 Release v1, 0.0(12 Jun. 2001.))
FIG. 1 is a diagram illustrating the architecture of the WCDMA communication system stipulated in the 3GPP.
The WCDMA communication system has an architecture in which RAN (Radio Access Network) 91 is connected with CN (Core Networks) 93 that provides a circuit switching or packet switching service in its own network.
RAN 91 has at least one (two in FIG. 1) radio network controller (RNC) 94, 95 and at least one (four in FIG. 1) NodeB (radio base station) 96 to 99.
RNCs 94, 95 are connected with CN 93 through the lu interface. In addition, RNCs 94, 95 are interconnected through the lur interface. Further, each of NodeBs 96 to 99 is connected to any one of RNCs through the lub interface.
Each of NodeBs 96 to 99 covers at least one cell 910 and is connected to User Equipment (UE: radio mobile station) 92 through the wireless interface. Each of NodeBs 96 to 99 terminates the wireless interface and transmits user data to RNC.
RNC 94, 95 sends and receives control signals for signaling control with UE 92 though any one of NodeBs to deal with establishing or releasing a call. RNC 94, 95 controls NodeBs under control thereof to send and receive user data with UEs.
In the WCDMA communication system in the 3GPP system as shown in FIG. 4, RNC 94, 95 has both the function of Control plane (C-plane), which deals with a control signal and the function of User plane (U-plane), which processes user data. As a result, when enhancing the processing capability of the C-plane is required, it is necessary to establish a new RNC, in addition to the existing RNCs, even if no enhancement of the processing capability of the C-plane is required, which potentially entails a redundant increase in a system cost.
In contrast, a radio access network has been intended in which the process of the C-plane and the process of the U-plane are allocated to separate devices and freedom of the system architecture is increased to appropriately define the processing capabilities of the C-plane and the U-plane properly defined and to provide an optimally adapted architecture for the system requirement.
According to this system, the system requirements may be met, and the system cost may be reduced, by adding devices for the C-plane process and the U-plane process on an as-needed basis.
The above-described prior technique, however, is problematic in the points described below.
In dividing an RNC into a device for dealing with the C-plane (hereinafter referred to as a C-plane processing device) and a device for processing the U-plane (hereinafter referred to as a U-plane processing device), the cell information which only should be held in one RNC so far, have to be commonly set and held in both of the C-plane and U-plane processing devices. The cell information includes the information to be set on a cell-by-cell basis to identify a cell. The cell information includes the information established for every cell, for example, a cell ID, a local cell ID, etc., and a mobile country code (MCC), a mobile network code (MNC), a local area code (LAC), etc.
Moreover, when a cell is newly established or established in addition to already existing RNCs, it is required to set the cell information of both of the C-plane and U-plane processing devices, which complicates the operation. In addition, discordance can be introduced between the information items set in the C-plane and U-plane processing devices, so that the system will not operate normally. In such a case, it is conceivable that a great deal of effort will be wasted to find the discordance.
It is an object of the present invention to provide a radio access network that allows added or modified cell information to be reliably and easily set when a new cell is established additionally or newly, in the environment in which a radio network controller defined in the 3GPP is divided into the C-plane processing device and the U-plane processing device.